Method for developing finger prints



Dec. 22, 1970 c MCDQNALD ETAL 3,549,397

METHOD FOR DEVELOPING FINGER PRINTS Filed Feb. 5, 1969 ZZdoZZ a mfmZ/ w, ATTORNE Y5 FIG. 4

Patented Dec. 22, 1970 METHOD FOR DEVELOPING FINGER PRINTS Hugh C. McDonald, Santa Monica, Thomas J. Nolan,

La Canada, and George W. Hoifer, Huntington Beach,

Calif., assignors to World Associates, Inc., a corporation of California Filed Feb. 3, 1969, Ser. No. 796,084 Int. Cl. B41n 3/00 US. Cl. 117-5 1 Claim ABSTRACT OF THE DISCLOSURE A method for developing finger prints includes the confining of a mixture of carbon particles and iron filings in a cavity. A cover is positioned over this cavity and a guide means is provided on the cover enabling manual movement of a magnet over the cavity. The arrangement is such that a card or medium upon which a persons finger print has been impressed may be inserted under the cover in a position to overlie the cavity. The magnet is then manually moved into proximity to thereby attract the mixture against the surface of the card and result in the adherence of the mixture to the impression formed on the surface of the card to render the finger print visible.

This invention relates generally to finger printing methods and more particularly, to a novel finger printing method for rendering immediately visible, finger impressions on a given medium.

BACKGROUND OF THE INVENTION In taking a persons finger prints for purposes of identification, the usual practice is to provide an inked stamp pad or similar inked surface periodically rolled with an ink roller to be maintained in proper condition. The person then impresses his finger on this surface to pick up the ink. Thereafter, the person presses his finger on a card or other medium upon which the finger print record is to be maintained. Finally, the person is then supplied with a suitable detergent solution or other means for removing the ink from his finger.

The foregoing process is not only time consuming, but is somewhat annoying to the person who must remove ink from his fingers after the procedure is completed. Moreover, the filing of the finger print card must be delayed until the ink has dried.

Many of the foregoing annoyances can be overcome by simply having a person impress his finger on a suitable medium such as a card without using any ink. The impression on the card is then developed as by brushing the same with a suitable powder mixture usually consisting of carbon particles. While the quality of the resulting print will hardly match that obtained by the conventional ink methods, the developed print is sufiicient for most purposes of identification and is least annoying to the person whose print is taken. Further, the print on the card is dry and the card can ordinarily be filed immediately.

There still exists, however, the problem of an operator brushing on the carbon mixture to develop the print. The developing mixture itself is generally messy to deal with and the mere process of brushing the finger impression with the developing mixture must be carefully carried out to avoid soiling other portions of the card or other objects in the immediate area.

Because of some of the foregoing factors, the use of a finger print or thumb print as a ready means of identification on checks, passports, and similar commercial papers has not gained wide acceptance. In fact, the major use of finger prints is still confined to the identification of criminals, persons in high security positions, some alien groups and other similar classifications.

BRIEF DESCRIPTION OF THE PRESENT INVENTION With the foregoing in mind, it is a primary object of the present invention to provide a novel finger printing method which will enormously simplify the taking of a persons finger prints for ready means of identification without the attendant disadvantages described heretofore.

Briefly, one means for carrying out the method includes a box shaped base member defining a cavity incorporating a finger print developing powder mixture. This powder mixture includes magnetically attractive particles such as iron filings together with a suitable developer such as carbon particles. A fiat cover is hinged to the top of the base member in a position to overlie the cavity. A guide frame in turn is secured to this cover and serves to movably mount a permanent magnet such that the magnet may be brought in close proximity to the mixture in the cavity. In accord with the method a suitable medium such as a card may be impressed on one surface with a persons finger print without any special ink. This surface of the card is then positioned between the cover and base member with the surface facing the interior of the cavity and thus the mixture in the cavity. The magnet is then manually guided by the guide means into close proximity to the cavity thereby drawing up the mixture against the surface of the card resulting in the carbon particles adhering to the impressions of the finger print to thereby render the print visible. Removing the magnet from the proximity of the cavity permits excess particles in the mixture to fall back into the cavity. The card is then removed.

With the foregoing method a persons finger prints may be developed extremely rapidly and without any inconcenience since at no time it is necessary for an operator to physically manipulate the finger print developer powder. Moreover, the card may be immediately removed from its position under the cover overlying the cavity after the magnet has been removed from the vicinity of the cavity, and placed in a suitable card file.

BRIEF DESCRIPTION OF THE DRAWINGS A better understanding of the invention will be had by now referring to one embodiment for carrying out the method as illustrated in the accompanying drawings, in which:

FIG. 1 is a perspective view of the basic components making up a finger print developer for carrying out the method of the invention;

FIG. 2 is a cross section illustrating the manner in which the device is operated;

FIG. 3 is another cross section similar to FIG. 2 showing the relative position of various components during a subsequent step in the development of a finger print; and,

FIG. 4 is a plan view of a card medium showing the developed finger print.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, there is shown a base member 10 of generally rectangular box shape having a cover 11 hinged to the upper rear edge of the base member as at 12. A resilient metal clip 13 may be provided on the front of the base member 10 for engaging the front edge of the cover 11 to hold it closed in flush position against the top surface of the base member. The base member 10 and cover 11 may both constitute plastic material.

As shown by the phantom lines in FIG. 1, the base member 10 includes on its top surface a cavity 14 containing a mixture in the form of a powder 15. This mixture includes magnetically responsive particles such as iron filings and in addition a suitable developer such as carbon particles. When the cover 11 is closed against the top surface of the base member as illustrated in FIG. 1, the mixture 15 is completely entrapped within the structure.

A guide frame in the form of a cylinder 16 is secured to the top of the cover 11 and extends vertically away therefrom as shown.

This guide frame serves to movably support a plunger 17 extending through the upper end of the cylinder for vertical up and down movement. The plunger 17 terminates at its lower end in a permanent magnet 18 and at its upper end in a knurled knob 19. A coiled biasing spring 20 is disposed between the under side of the knob 19 and the top surface of the cylinder 16 and normally biases the plunger 17 in an upward direction. In FIG. 1, the plunger 17 and permanent magnet 18 are shown in an intermediate position within the cylinder 16.

Referring now to the right portion of FIG. 1 there is shown in exploded view a medium in the form of a card 21 having top and bottom surfaces 22 and 23 and a designated surface area 24 for a receiving a persons finger print. In the particular embodiment of the invention illustrated, the card is designed to receive a persons right thumb print but it should be understood that any one or more of his fingers could be used. In the present description, the term finger print is meant to include any one finger or a persons thumb print or combination thereof.

It will be evident from FIG. 1 that the card 21 is dimensioned to be co-extensive with the rectangular dimensions of the base member 10 and cover 11. The arrangement is such that the card may be sandwiched between the cover 11 and top surface of the base member 10.

FIG. 2 illustrates in cross section the card 21 in proper position on the base member 10. In FIG. 2 it will be noted that the front clip 13 has been removed and the cover 11 raised about the hinge 12 to facilitate insertion of the card. It will be noted in both FIGS. 1 and 2 that by making the dimensions of the card co-extensive with those of the base member and cover, the under surface area 24 upon which a print has been impressed will automatially be properly positioned over the cavity 14 when the card itself is properly registered between the cover 11 and base member 10.

FIG. 3 illustrates the unit with the cover 11 closed to sandwich the card 21 between the cover and top surface of the base member 10.

FIG. 4 illustrates the card 21 wherein there has been rendered visible a finger print as shown at 29.

OPERATION The overall operation of the finger print developer will now be described.

When it is desired to take a persons finger print for ready means of identification, it is only necessary to have the person impress his print in the area 24 of the card 21 as shown in FIG. 1. This operation does not require any inking or the like and in fact will automatically be effected if the card is simply handed to a person. After the persons print has been impressed on the area 24, the card is flipped over as indicated by the arrow 25 and moved in the direction of the arrow 26. The cover 11 on the base member 10 is raised as illustrated in FIG. 2 and the card placed on the top surface of the member 10 to overlie the cavity 14. The cover 11 is then swung downwardly on top of the card to sandwich the same be- 4 tween the cover and the base member as illustrated in FIG. 3.

The operator then grasps the knob 19 and urges the plunger 17 downwardly as indicated by the arrow 27. Thereafter, the knob 19 is twirled as indicated by the arrow 28 causing the permanent magnet 18 to sweep over the top surface of the cover 11 in close proximity to the cavity and mixture in the cavity. This action will attract the mixture against the surface of the card 21 as shown at 15' resulting in adherence of the carbon particles to the impressions formed on the surface to thereby render the finger print visible.

When the knob 19 is released, the plunger is automatically returned to its up position thereby removing the influence of the magnet 18 so that any excess mixture falls back into the cavity. The card 21 can then be removed and immediately filed. The resulting print will be as illustrated at 29 in FIG. 4.

From the foregoing description, it will be evident that the present invention has provided a very convenient method for developing finger prints. Not only is the annoyance of inking a persons finger avoided, but the application of the developing powder can be wholly carried out without any physical contact therewith by the operator. In this respect, it should be noted that the magnet 18 itself is always isolated from actual physical contact with the particles in the mixture by the cover 11. Thus if the operator makes sure to release the plunger 17 before raising the cover 11, there will not result any scattering of the particles from the cavity and environmental areas may always be kept clean.

It should be understood that While the particular medium for receiving a persons finger print has been described as a card such as a conventional 3 x 5 filing card, the medium may constitute a check, passport, or other commercial paper or instrument upon which an identifying print is desired.

What is claimed is:

1. A method of developing finger prints comprising the steps of:

(a) confining a mixture of iron filings and carbon particles in a cavity;

(b) impressing a finger print on a surface of a medium;

(c) positioning said medium over said cavity with said surface facing downwardly towards said mixture;

((1) positioning a cover over said medium to hold said medium flat;

(e) providing a guiding means on said cover for holding a magnet;

(f) manually moving said magnet in said guiding means above said cavity over said cover to thereby attract the said mixture onto said surface of said medium and result in adherence of said carbon particles to the impressions formed on said surface to render said finger print visible; and

(g) removing said medium from under said cover.

References Cited UNITED STATES PATENTS 2,874,063 2/1959 Greig 117-l7.5 2,986,831 6/1961 Terek et al 1l70.5UX 3,075,852 1/1963 Bonora l170.5 3,132,036 5/1964 MacDonell 117-05 3,202,092 8/1965 Childress 1011l4 3,408,217 10/1968 Obuchi 1l83l.5X 3,492,140 1/1970 Honjo et al. 1183l.5X

MORRIS KAPLAN, Primary Examiner US. Cl. X.R. 

